i2c: Optimize function i2c_detect()

Check the class flags before allocating the temporary i2c_client
structure, to avoid allocating it when we don't need it.

Also optimize the inner loop a bit.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>

diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index bdadfaf..d231f68 100644 (file)
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -1508,26 +1508,25 @@ static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
        if (!driver->detect || !address_list)
                return 0;
 
+       /* Stop here if the classes do not match */
+       if (!(adapter->class & driver->class))
+               return 0;
+
        /* Set up a temporary client to help detect callback */
        temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
        if (!temp_client)
                return -ENOMEM;
        temp_client->adapter = adapter;
 
-       /* Stop here if the classes do not match */
-       if (!(adapter->class & driver->class))
-               goto exit_free;
-
        for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
                dev_dbg(&adapter->dev, "found normal entry for adapter %d, "
                        "addr 0x%02x\n", adap_id, address_list[i]);
                temp_client->addr = address_list[i];
                err = i2c_detect_address(temp_client, driver);
-               if (err)
-                       goto exit_free;
+               if (unlikely(err))
+                       break;
        }
 
- exit_free:
        kfree(temp_client);
        return err;
 }